Why are the Nexus One Linpack scores so much higher than on my phone?
Sep 5th
I get all sorts of comments directly to me and I see them posted on many boards. Generally, people want to know why their phone doesn’t show the leap in the Linpack score when they run Froyo that others see on the Nexus One, Droid Incredible, or the EVO 4G. The one word answer: NEON.
After looking into it for a while, I was focusing on what makes the Nexus One so much better than the other phones. On the chip level, I didn’t see it. Then it dawned on me to look at what Google had to say on the matter. Well, it was there in black and white. In their 20 May 2010 Developer’s Blog entry (http://android-developers.blogspot.com/2010/05/android-22-and-developers-goodies.html) they say that people could see a 2-5x speed increase. I think it is pointed out in an entry later in the blog dealing with NDK, which I initially missed: “ARM Advanced SIMD (a.k.a. NEON) instruction support The NEON instruction set extension can be used to perform scalar computations on integers and floating points. However, it is an optional CPU feature and will not be supported by all Android ARMv7-A based devices. The NDK includes a tiny library named “cpufeatures” that can be used by native code to test at runtime the features supported by the device’s target CPU.”
So, I guess this means that NEON is the difference. If your phone’s CPU has it and it’s enabled for JIT, you can expect higher Linpack numbers.
Froyo for Galaxy S Spotted here first
Aug 30th
If you had an eagle eye and watched the Latest Posts here for Linpack, you would have seen the GT-i9000 posted a Linpack score on 26 Aug. This was before it was announced a couple of days ago as being leaked and in the wild. See: http://www.samsunghub.com/2010/07/28/galaxy-s-i9000-android-2-2-build-leaked/
Now the score that day was 13.415, which not what I was hoping. I have a Vibrant and I would like to see a number like the Nexus One or Droid Incredible. It’s still better than the 8s that I have been getting.
I’m more interested in getting the GPS and compass fix first.
Also, if you looked at the smdkc110 (Samsung Development Kit), you’ll see that it is running a GT-I9000 ROM too. The best score there is 20.7, so hopefully they have some more tweaking to do.
KISS
Aug 10th
I try to follow the KISS principle… Keep It Simple Stupid.
I haven’t updated Linpack in a long time and I knew that I need to make some major changes. So, I updated the app this morning with the first major change in almost 4 months. I increased the matrix that is calculated from 200×200 to 500×500. This change was done to hopefully reduce the number of erroneous MFLOPS numbers. With the matrix at 200, times were starting to get well under 1 second. This is not good for a timing benchmark. Since FroYo is taking over, the matrix had to be
enlarged to make the calculation take longer. This happened with the Java Linpack in the 90s, with faster systems they had to increase the size of the matrix too.
Don’t be surprised if your Linpack run takes up to 6 times longer to run, it’s supposed to do that. Look at the resulting MFLOPS over several runs; hopefully they will be more consistent.
I also updated the Mhz value obtained to show the actual Mhz the system is running at the end of the Linpack run. And I included a new button for the Latest Runs. This shows the latest runs by everyone (slow or fast) over the last few days.
Android 2.2 Leads
Jul 13th
Android 2.2 (FroYo) took the Linpack lead for the most runs this last week. According to my analytics, Android 2.2 was used 43.1% of the time. Android 2.1-update1, the previous leader was used 39.8% of the time. So what was used for the rest of the 17% of the time? How about 158 other ROMs! That is a lot of variety to choose.
Mixed in with the lot is some curious ROMs; Android 3.0, Android 3.0.1 and Android 3.2
Google I/O 2010 included Linpack
Jun 26th
I have been looking thru some of the Google I/O videos from the conference when I saw a mention of Linpack in the talk about “A JIT Compiler for Android’s Dalvik VM”. Check out the video and keep a lookout at 24:27 mark.
A JIT Compiler for Android\’s Dalvik VM